A statistical study of the plasma and composition distribution inside magnetic clouds: 1998-2011
| Autor: | Ake Zhao, Zamri Zainal Abidin, Yuandeng Shen, Oloketuyi Jacob, Jin Huang, Yu Liu, Hengqiang Feng |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Flux FOS: Physical sciences Astronomy and Astrophysics Magnetic reconnection Charge (physics) Plasma Electron 01 natural sciences Space Physics (physics.space-ph) Standard Model Ion Astrophysics - Solar and Stellar Astrophysics Physics - Space Physics Space and Planetary Science 0103 physical sciences Physics::Space Physics Astrophysics::Solar and Stellar Astrophysics Atomic number Atomic physics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| Popis: | A comprehensive analysis of plasma and composition characteristics inside magnetic clouds (MCs) observed by the Advanced Composition Explorer (ACE) spacecraft from 1998 February to 2011 August is presented. The results show that MCs have specific interior structures, and MCs of different speeds show differences in composition and structure. Compared with the slow MCs, fast MCs have enhanced mean charge states of iron, oxygen, silicon, magnesium, $\mathrm{O^{7+}/O^{6+}}$, $\mathrm{C^{6+}/C^{5+}}$, $\mathrm{C^{6+}/C^{4+}}$ and $\mathrm{Fe^{\geq16+}/Fe_{total}}$ values. For ionic species in fast MCs, a higher atomic number represents a greater enhancement of mean charge state than slow MCs. We also find that both the fast and slow MCs display bimodal structure distribution in the mean iron charge state ($\mathrm{\langle Q\rangle Fe}$), which suggests that the existence of flux rope prior to the eruption is common. Furthermore, the $\mathrm{\langle Q\rangle Fe} $, $\mathrm{Fe^{\geq16+}/Fe_{total}}$, and $\mathrm{O^{7+}/O^{6+}}$ ratio distribution inside fast MCs have the feature that the posterior peak is higher than the anterior one. This result agrees with the "standard model" for CME/flares, by which magnetic reconnection occurs beneath the flux rope, thereby ionizing the ions of the posterior part of flux rope sufficiently by high-energy electron collisions or by direct heating in the reconnection region. 11 pages,3 figures |
| Databáze: | OpenAIRE |
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